When cooking steaks, don’t mess with them on the grill. Flip them just once for the perfect charred crust.
This is false. Per Serious Eats:
The Theory: EVERYBODY says this one, and they say it not just for steaks, but for burgers, lamb chops, pork chops, chicken breasts, you name it. The Reality: The reality is that multiple flipping will not only get your steak to cook faster—up to 30% faster!—but will actually cause it to cook more evenly, as well. This is because—as food scientist and writer Harold McGee has explained—by flipping frequently, the meat on any given side will neither heat up nor cool down significantly with each turn.